Three stage manual knife sharpener



FIG. 1 is a perspective view of a three stage manual knife sharpener showing our new design;

FIG. 2 is a right side elevational view thereof with the left side being identical;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The broken lines in FIG. 6 illustrate portions of the design that form no part of the claim. 

The ornamental design for a three stage manual knife sharpener, as shown and described. 